If the instrument under which any real and personal property were or are given, granted, conveyed, bequeathed, devised to, or otherwise vested in, confided to, or awarded to, the city upon charitable use or trust shall limit or restrict the investment of such property or the proceeds thereof to assets of the class authorized by law as legal investments, the city may invest and reinvest moneys of the use or trust in any such common trust fund maintained by the city, provided the assets composing such fund consist solely of assets of the class authorized as legal investments for funds held by fiduciaries.
53 P.S. § 5503